1. Field of the Invention
The present invention relates to an ethylene-α-olefin copolymer. More particularly, the present invention relates to an ethylene-α-olefin copolymer excellent in balance between mechanical strength and processability.
2. Description of Prior Art
Ethylene polymers are molded into a film, sheet, bottle and the like by various molding methods such as inflation molding, T-die cast molding, blow molding, injection molding and the like, and used in various applications. Such ethylene polymers are required to have excellent processabilities such as small motor load in melt extrusion by an extruder, stability of bubble in inflation molding, no drooping down of a parison in blow molding, and the like. There are suggested, for example, a polymer obtained by polymerization of ethylene using a polymerization catalyst composed of silica supporting methylalumoxane, a specific metallocene complex and triisobutylaluminum, a polymer obtained by polymerization of ethylene using a polymerization catalyst composed of a specific metallocene complex, silica supporting methylalumoxane and triisobutylaluminum (see, e.g., JP 8-59741A and 9-235312A), and the like. Further suggested are a polymer obtained by copolymerization of ethylene and α-olefin using a catalyst formed from racemic-ethylenebis(1-indenyl)zirconium diphenoxide, triusobutylaluminum and a co-catalyst carrier obtained by contacting diethylzinc with pentafluorophenol, then, contacting silica treated with hexamethyldisilazane, then, contacting water (see, e.g., JP2003-171412A); a polymer obtained by copolymerization of ethylene and α-olefin using a catalyst formed from racemic-ethylenebis,(1-indenyl)zirconium diphenoxide, triisobutylaluminum and a co-catalyst carrier obtained by contacting diethylzinc with silica treated with hexamethyldisilazane, then, contacting pentafluorophenol, then, contacting water (see, e.g., JP 2004-149760A and 2005-97481A), and the like.
However, the above-mentioned ethylene polymers are not sufficiently satisfactory in mechanical strength or processability in some cases.